------------[ cut here ]------------
WARNING: CPU: 1 PID: 6909 at kernel/rcu/tree_stall.h:1001 rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:993
Modules linked in:
CPU: 1 PID: 6909 Comm: syz.2.437 Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026
RIP: 0010:rcu_check_gp_start_stall+0x2dc/0x460 kernel/rcu/tree_stall.h:1001
Code: ff ff ff 48 c7 c7 a0 64 31 97 be 04 00 00 00 e8 7a eb 6d 00 48 89 df b8 01 00 00 00 87 05 7c e2 bf 15 85 c0 0f 85 19 ff ff ff <0f> 0b 48 81 ff c0 73 13 8d 74 47 48 c7 c0 1c 9b 8b 8e 48 c1 e8 03
RSP: 0018:ffffc900001f0bb8 EFLAGS: 00010046
RAX: 0000000000000000 RBX: ffffffff8d1373c0 RCX: ffffffff81718216
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffffff8d1373c0
RBP: ffffc900001f0e30 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: fffffbfff2e62c94 R12: 0000000000002904
R13: ffffffff8d1373c0 R14: 0000000000000a02 R15: dffffc0000000000
FS:  00007fe3e68d56c0(0000) GS:ffff8880b8f00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b2fe63f9b CR3: 0000000077fd3000 CR4: 00000000003506e0
Call Trace:
 <IRQ>
 rcu_core+0x635/0x1770 kernel/rcu/tree.c:2462
 handle_softirqs+0x280/0x820 kernel/softirq.c:578
 __do_softirq kernel/softirq.c:612 [inline]
 invoke_softirq kernel/softirq.c:452 [inline]
 __irq_exit_rcu+0xd3/0x190 kernel/softirq.c:661
 irq_exit_rcu+0x9/0x20 kernel/softirq.c:673
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1088 [inline]
 sysvec_apic_timer_interrupt+0xa4/0xc0 arch/x86/kernel/apic/apic.c:1088
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:687
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:104 [inline]
RIP: 0010:__local_bh_enable_ip+0x142/0x1c0 kernel/softirq.c:413
Code: 8a e8 12 06 36 09 65 66 8b 05 ca 4a b1 7e 66 85 c0 75 54 bf 01 00 00 00 e8 0b 22 0a 00 e8 16 33 3b 00 fb 65 8b 05 96 4a b1 7e <85> c0 75 05 e8 95 31 ae ff 48 c7 04 24 0e 36 e0 45 4b c7 04 37 00
RSP: 0018:ffffc90004c1fa80 EFLAGS: 00000282
RAX: 0000000080000000 RBX: 0000000000000200 RCX: 184fa06f78dac100
RDX: dffffc0000000000 RSI: ffffffff8acacbe0 RDI: ffffffff8b1c9c20
RBP: ffffc90004c1fb10 R08: ffffffff8e8b666f R09: 1ffffffff1d16ccd
R10: dffffc0000000000 R11: fffffbfff1d16cce R12: ffffffff8131d952
R13: 0000000000000000 R14: dffffc0000000000 R15: 1ffff92000983f50
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 fpregs_unlock arch/x86/include/asm/fpu/api.h:80 [inline]
 restore_fpregs_from_user arch/x86/kernel/fpu/signal.c:331 [inline]
 __fpu_restore_sig arch/x86/kernel/fpu/signal.c:359 [inline]
 fpu__restore_sig+0x9d7/0x11c0 arch/x86/kernel/fpu/signal.c:493
 restore_sigcontext arch/x86/kernel/signal_64.c:95 [inline]
 __ia32_sys_rt_sigreturn+0x6e2/0x860 arch/x86/kernel/signal_64.c:266
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fe3e599ce57
Code: 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 <0f> 05 48 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89
RSP: 002b:00007fe3e68d50e8 EFLAGS: 00000246
RAX: 00000000000000ca RBX: 00007fe3e5c15fa8 RCX: 00007fe3e599ce59
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 00007fe3e5c15fa8
RBP: 00007fe3e5c15fa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe3e5c16038 R14: 00007ffe64443b40 R15: 00007ffe64443c28
 </TASK>
----------------
Code disassembly (best guess):
   0:	8a e8                	mov    %al,%ch
   2:	12 06                	adc    (%rsi),%al
   4:	36 09 65 66          	ss or  %esp,0x66(%rbp)
   8:	8b 05 ca 4a b1 7e    	mov    0x7eb14aca(%rip),%eax        # 0x7eb14ad8
   e:	66 85 c0             	test   %ax,%ax
  11:	75 54                	jne    0x67
  13:	bf 01 00 00 00       	mov    $0x1,%edi
  18:	e8 0b 22 0a 00       	call   0xa2228
  1d:	e8 16 33 3b 00       	call   0x3b3338
  22:	fb                   	sti
  23:	65 8b 05 96 4a b1 7e 	mov    %gs:0x7eb14a96(%rip),%eax        # 0x7eb14ac0
* 2a:	85 c0                	test   %eax,%eax <-- trapping instruction
  2c:	75 05                	jne    0x33
  2e:	e8 95 31 ae ff       	call   0xffae31c8
  33:	48 c7 04 24 0e 36 e0 	movq   $0x45e0360e,(%rsp)
  3a:	45
  3b:	4b                   	rex.WXB
  3c:	c7                   	.byte 0xc7
  3d:	04 37                	add    $0x37,%al